League-of-legends – How much honor must I have to earn badges

You have one false assumption in your question: what you observed was not two quests, but rather only one.

In other words, the quest was "Capture Point X, while defending point Y from Capture". The quest lasts until one team manages to capture the other, which means, in your case, the 'defend' portion of the quest lasts until your team manages to capture the enemy point in question, rather than a simpler, "defend for X".

You could theoretically have to defend that point for the rest of the game, as long as neither of the two target points changes hands.

Purely speaking of dragon vs tower. The dragon is a better option.

• The dragon gives more gold. (750 vs 975).
• What you lose from the tower will be won back once you killed the enemy tower.
• The enemy team wont be killing the dragon over the next 6 minutes, you will not have to defend that dragon.
• You don't need to defend that tower either.

That said, dragon is not the top lane responsibility.

It's strongly situational. If you can save both, just save the tower first and then do dragon. If the enemy or minions are killing bot or mid tower, it's easy to defend it. You probably already have 3 people at the dragon, and now you simply gank bot or mid before you go back to dragon. Or dispatch 1 and do the dragon with just 2 people.

If we're speaking of the first 3 towers, those will fall eventually anyway, and are not worth that much post laning phase. If we're talking inhibitor towers or base tower, you MUST defend those before doing dragon.

At the very least, make sure you keep the dragon warded and keep the enemy team away from it. That is a good job for the jungler and the support. If i had to choose between killing a enemy tower, or preventing my enemy from killing the dragon, i would certainly save the dragon.

Getting dragon and keeping tower is of course the best option. The responsibility for killing the dragon lies at the bot laners early game. They should push or win there lane, and then kill dragon. If any jungler is around, the route around level 6 or 7 should be either gank bot->dragon or just call bot->dragon. If it's not possible to do the dragon at this point because of enemy aggression (and map control), keep the dragon warded and prevent the enemy team from taking it instead.